Various methods have heretofore been devised in order to supply liquified petroleum gas (LPG) to an internal combustion engine.
For example, U.S. Pat. No. 4,485,792 teaches that upon starting of an automobile, the engine aspirates air through the intake manifold where the flow rate meter undergoes a certain deflection out of its position of rest, whereby a metering piston is displaced as well by means of a lever. In accordance with the position of the metering piston, the limiting surface of the metering piston opens the metering opening to a greater or lesser extent towards an annular groove so that a quantity of LPG is metered at the metered valve which is dependent on the quantity of aspirated air ascertained by the air flow rate meter.
Moreover, U.S. Pat. No. 4,503,831 teaches apparatus which includes a vaporizer pressure regulating valve downstream of which a metering valve having a metering piston is disposed which is being moveable in a guide bore which opens a metering opening to a greater or lesser extent.
Moreover, U.S. Pat. No. 4,509,479 relates to apparatus for the air injection of liquid gas whereby the mixture of liquid gas and air can be influenced by a control pressure prevailing in a control chamber at the metering piston, and the control pressure is influenced by a control pressure regulating valve and the moveable valve element of which is engaged on one said by the intake tube pressure upstream of the air flow rate meter.
Yet another arrangement is shown by U.S. Pat. No. 4,489,700 which relates to a method for supplying an internal combustion engine with liquified petroleum gas as fuel and to an fuel supply system for an internal combustion engine which supplies the LPG to the engine. Finally, U.S. Pat. No. 1,954,968 teaches automatic fuel proportioning device for gas engines.
It should be noted that the prior art patents referred to herein basically relate to a system for metering LPG.
Natural gas has, over the recent years, become a more popular fuel source for internal combustion engines for a variety of reasons, including the sensitivity of the general public in attempting to free our environment of pollutants. In this regard, it is generally felt that natural gas which is used as a fuel source produces less pollutants than LPG. Accordingly, various kits and other mechanisms have been utilized in the past in order to convert LPG internal combustion engines to run on natural gas.
It is an object of this invention to provide an improved apparatus for metering the supply of natural gas to an internal combustion engine which may be initially installed in an internal combustion engine, or be used as a kit in order to convert an internal combustion engine running on natural gas, rather than LPG.
The broadest aspect of this invention relates to apparatus for metering the supply of natural gas to an internal combustion engine having an air intake manifold and throttle valve mounted therein comprising a pressure regulator for regulating the pressure of said natural gas, a sensor plate associated with said air intake manifold and moveable in response to variations in said throttle valve being actuable by said moveable sensor plate to vary the supply of natural gas to said air intake manifold in response to variations in said throttle valve so as to meter the supply of natural gas to said internal combustion engine.
It is another aspect of this invention to provide a method for metering the supply of natural gas to an air intake manifold having, a throttle mounted therein for an internal combustion engine comprising the steps of regulating the pressure of said natural gas from a natural gas cylinder, metering said regulated natural gas by a valve so as to apply said metered natural gas to said air intake manifold actuating said valve by sensor plate associated with said intake manifold, said sensor plate responding to variations in said throttle so as to meter the supply of natural gas to said air intake manifold.